[Coral-List] The myth of 100% coral cover

Eugene Shinn eshinn at marine.usf.edu
Mon Mar 19 14:18:24 EDT 2012

The answer is preserved in the rocks also known as Geology. The upper 
Florida Keys is a Pleistocene coral reef formed about 120,000 years 
ago when sea level was around 26 ft above present. Studies of the 
excellent exposure show that about 49 percent of the "reef" is/was 
along with various coralline red algae, coral sand, forams etc. So 
the reefs was approximately 50% coral back when there were no 
polluters around. Similar observations can be made throughout the 
List readers may be interested in a paper by C. T. Perry et. al., 
soon to be published in the Journal Geology. The title is: "Evidence 
of very rapid reef accretion and reef growth under high turbidity and 
terrigenous sedimentation." Basically the paper demonstrates 
(evidence from coring and C14 age dating) that some reefs well 
landward of the Great Barrier reef have accreted faster than the 
Barrier reef where the water is clear and oligotrophic. Apparently 
the coral grow well, and possibly most important, are protected from 
bio erosion when they die because the the coating of terrigenous 
sediment. We see something similar in Florida where the main outer 
reef tract is less than a meter thick while reefs in muddy waters 
closer to shore have been shown to be several meters thick. Gene

No Rocks, No Water, No Ecosystem (EAS)
------------------------------------ -----------------------------------
E. A. Shinn, Courtesy Professor
University of South Florida
College of Marine Science Room 221A
140 Seventh Avenue South
St. Petersburg, FL 33701
<eshinn at marine.usf.edu>
Tel 727 553-1158---------------------------------- 

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